This invention relates to the area of wireless telecommunications networks and, more specifically, to a tool for determining radio frequency coverage trouble spots in cells in a wireless network.
All wireless telecommunications service providers attempt to maximize usage of their networks, provide uninterrupted service for all network users and keep the cost of providing these services to a minimum. There are many tradeoffs involved between the first two goals when compared to the third. One aspect of wireless communications where the tension between these goals may be seen is in radio frequency coverage trouble spots within cells in the wireless network.
The geographic region served by a wireless network is divided into a plurality of areas known as xe2x80x9ccellsxe2x80x9d. Each cell includes a base station to provide a radio frequency (RF) connection between the public switched telephone network (PSTN) and wireless stations in the cell. When the geographic region is first divided into cells, the cells are engineered to provide coverage for the anticipated wireless station usage. Further, the cell is engineered to take into account topological aspects of its sub-region, such as tall buildings, highway traffic and geological formations such as mountains.
Only when the wireless network is placed into service is the accuracy of the engineering assumptions tested. There may be areas of high usage in the cell that were not anticipated at the time the cell was engineered. Further, there may be dead spots that were unanticipated. The service provider receives complaints regarding inability to place calls (in congested areas) and cutoffs or no response from the wireless system (in the dead spots). The service provider then must send out a specially equipped truck (or several trucks) to determine the location and extent of the problems. In most cases, the service provider adds repeaters or supplemental xe2x80x9cmicroxe2x80x9d or xe2x80x9cpicoxe2x80x9d cells to provide coverage in the hot and dead spots. In many cases, however, additional micro cells to alleviate congestion are frequently over engineered and one (or more) of the micro cells end up lightly loaded. The service provider has thus unnecessarily increased cost while providing modestly improved service.
Therefore, a problem in the art is that RF coverage problems within a cell are determined through expensive effort and still may be insufficient or overly sufficient.
This problem is solved in technical advances achieved in the art by a system and method that rapidly and precisely determines the geographical area of high concentration of usage (hot spots), areas of poor RF frequency reception (dead spots), and areas of handoff thrashing. The number of failed call attempts, dropped calls land the like, are measured. The identification of a wireless station and its location are recorded at selected points during a call. If a high number of uncompleted, dropped or handed off calls are recorded, then the base station uses the last known location of the wireless stations that report trouble to circumscribe an area in which the hot spot or dead spot occurs.